The present invention relates to a centrifugal decanter with continuous evacuation of the solid, for the processing of nuclear products.
Machines of this type are known, which generally comprise a mechanical zone separated from the active zone via a bearing structure in which a removable slab for biological protection is provided. The machine is generally a pendulous decanter operating by cycles, which comprises a vessel fixed to the bearing structure and inside which a decanter bowl is driven in rotation. The machine conventionally comprises a charging tank and a pipe which projects a jet of liquid under pressure for extraction of the decanted solid.
The vessel is provided with an evacuation of the clarified liquid, a retractable supply of the suspension to be decanted, and with a drain for the humid solid after decantation.
Operation of the machine by cycles requires that the flow be periodically stopped, this involving storage of the substance to be decanted. The decanted solid is eliminated by means of a jet of liquid under pressure which transforms it into a slurry which risks blocking the evacuation conduit. Moreover, due to its evacuation in humid form, the decanted solid comprises a quantity of liquid which reduces the quality of decantation of the substance.
The bowl of the machine is of large diameter in order to be able to place the different elements such as the charging tank and the pipe. The large dimension of the bowl requires a low speed of rotation due to the mechanical stresses, which implies a poor decantation of the substances. Finally, the larger the diameter of the bowl, the greater is the volume of substances to be treated, which is contrary to the processing of nuclear products.
It is a more particular object of the present invention to overcome these drawbacks.
The continuous decanter according to the invention has for an object to reduce the threshold of criticality for the same mass of processed product modifying its geometrical form while improving its quality.